Wireless communications has become pervasive throughout the world. Even though wireless communications carriers have placed communications access points extensively in metropolitan areas, there are many metropolitan areas that have poor wireless communications coverage provided by one or more wireless carriers. In other words, there are areas within or near cities that have “dead-zones” or are sparsely covered by one or more wireless carriers. Typically, the quality of wireless communications services is dictated by a number of factors, include density of communications antennas, power provided to the communications antennas, and natural and man-made obstacles, for example. Furthermore, rural areas in many countries of the world, including the United States, are not well equipped with wireless communications services. In the case of a wireless communications carrier not providing coverage in an area, the wireless communications carrier may have a roaming agreement with other wireless communications carriers so that its customers may roam onto the networks of the other wireless communications carriers.
In areas of lower coverage of wireless communications services, wireless devices, such as mobile telephones, personal digital assistants, games, or other wireless devices, can receive poor wireless communications services, which includes dropping communications links (e.g., dropping telephone calls) or having communications services that drops data due to communicating with a weak or marginal communications signal. A marginal communications signal typically occurs when a communications signal being received by the wireless device has a signal strength nearing the threshold sensitivity of the receiver (e.g., below −102 dBm). The specific value of a marginal communications signal may vary based on a variety of factors, including communications carrier definitions, wireless device performance, area in which wireless communications are being provided, and system specifications.
As previously described, wireless communications carriers form roaming agreements with one another to enable subscribers of the respective wireless communications carriers to roam between networks of the other wireless communications carriers. Each of the wireless communications carriers has a preferred list of communications carriers based on a number of factors, including revenue sharing arrangements and other contractual benefits for the respective wireless communications carriers. The wireless carriers typically store a preferred roaming list in wireless devices to enable the wireless devices to seek, in order of preference, the networks of wireless carriers identified on the preferred wireless carriers when roaming (i.e., when a wireless device is out of range of the communications carrier of the subscriber and connected to a network of another communications carrier). Roaming lists typically store system identifiers (SIDs) associated with respective communications carriers.
While a wireless device communicates with a wireless communications system, signal strength of a communications signal above a marginal communications signal generally provides a user with an acceptable communications signal to communicate with the wireless communications system. However, conventional wireless communications devices are configured to communicate with a communications signal until the communications link is ultimately dropped. This means that the wireless device may communicate with the wireless network using a marginal communications signal until the communications link is dropped. If a user of the wireless device places a call, for example, while the wireless device is in communication with a wireless access point while operating with a marginal communications signal, the call can be poor, which may cause static, information loss, or a drop during the call. In response to a communications link being dropped, the wireless device attempts to establish another communications link with a wireless access point of one of the communications carriers on the preferred roaming list.